The thermalization of a strongly coupled plasma is examined in the holographic framework through non-local observables: the equal-time two-point correlation function of a large dimension boundary operator, and Wilson loops of different shapes. The evolution of the probes from an initial far-from-equilibrium state to a hydrodynamic regime is found to depend on their size... A hierarchy among the thermalization times of the energy density, the pressures and the large size probes, is identified: the relaxation process is faster at short distances. (read more)